At the present time, there are known machines of different kind for preparing coffee, white coffee or similar infused beverages, comprising substantially one or more infusion units housed into a box-like housing and provided with a respective boiler for containing water, which is suitably heated by means of electric heating elements connected in the machine electric circuit, and one or more filters in which the ground coffee (or other raw material for the infusion) is introduced in advance, which filters are arranged on a position below the relative infusion units for permitting the heated water coming from the related boiler to pass therethough, thus preparing the coffee or other infused beverages.
Moreover, in the case in which such machines are arranged for preparing white coffee too, they also include one or more mixer-emulsifier units of per se known type, communicating with at least a milk containing receptacle housed into said machine box-like housing, on a position above the corresponding mixer-emulsifier unit. Then, in this case the milk is heated in advance in the machine and introduced on metered amounts thereof in the corresponding mixer-emulsifier, where it emulsifies itself with air at a pre-established ratio, thereby forming milk foam, which is subsequently introduced in the receptacle containing the coffee or other infused beverage which has been prepared in advance in the machine, by mixing with it therewith. These kinds of machines therefore permit to obtain coffee, white coffee or similar infused beverages with different operations, in which first of all are needed the 1) preparation of the ground coffee (or of the different raw materials for the other infused beverages), 2) the introduction in the corresponding filter thereof, which filter has been detached from the machine in advance, and subsequently coupled in the same machine, and finally 3) the introduction of the associated infusion unit for preparing the desired infused beverage, with the need to provide another mixing with the milk foam thereof, in case in which infused beverages mixed with milk have to be prepared.
Moreover, there is the need to clean the different filters after a prolonged operation period thereof, for being re-used in subsequent operations of the same kind and this makes complicated and less practical in use the operation and maintenance of these machines and permits the use thereof exclusively as machines for a bar, wherein they are able to prepare infused beverages generally in a limited and discontinuous frequency, and therefore do not lend themselves evidently for a use in which a continuous preparation of numerous infused beverages is required such as for example in community refectories and the like.